Ancillary ligand stabilized metal complexes (e.g., organometallic complexes) are useful as catalysts, additives, stoichiometric reagents, monomers, solid state precursors, therapeutic reagents, and drugs. The ancillary ligand system comprises organic substituents that bind to the metal centers, remain associated with the metal centers, and therefore, provide an opportunity to modify the shape and electronic and chemical properties of the active metal center(s) of the organometallic complex's active metal centers.
Certain organometallic complexes are catalysts for reactions such as oxidation, reduction, hydrogenation, hydrosilation, hydrocyanation, hydroformylation, polymerization, carbonylation, isomerization, metathesis, carbon-hydrogen activation, cross-coupling, Friedel-Crafts acylation and alkylation, hydration, dimerization, trimerization, oligomerization, Diels-Alder reactions, and other transformations. Organometallic complexes can be prepared by combining an ancillary ligand precursor with a suitable metal-containing precursor in a suitable solvent at a suitable temperature. For example, organometallic complexes are used for single-site, olefin polymerization catalysis. The active site typically comprises an ancillary-ligand-stabilized, coordinatively unsaturated, transition metal, alkyl complex.
PCT publication WO 99/05154 relates to a variety of pnictide-based ligands and their uses for catalyst systems. In particular, it discloses metal compositions and compounds, having an ancillary ligand structure, that polymerize non-functionalized and functionalized monomers, either alone or in the presence of an activator. The ancillary ligand structure is a chelating ligand that may optionally further connect to the metal.
Amidinato complexes of Group-3-6 metals are disclosed in U.S. Pat. No. 5,707,913 to Schlund et al. Group-4 bisamido catalysts are disclosed in U.S. Pat. No. 5,318,935 to Canich, et al., and related multidentate, bisarylamido catalysts are disclosed by D. H. McConville et al. Macromolecules 1996, 29, 5241-5243.
It is always a desire to discover new catalysts and catalyst systems as provided by these compositions and catalyst systems.